Mix half of the flour, yeast, sugar, and milk with a spatula.,______,Place Step 2 on top of a board, and knead while stretching it against a flat surface.,Knead well.,Knead with both hands once it rolls into a lump so that it doesn't dry out.,After it has become smooth from kneading, wrap in plastic wrap, cover with a wet towel, and let it rise once at 40C for 25~35 minutes.,Poke the dough with a floured finger, divide into 6 equal portions if it is ok, and roll into smooth balls.,Let sit for 10 minutes.,Shape it.,Lay the dough on a flat surface, the closed edges on top, press out the gas by hand, and sprinkle chocolate chips.,Roll it up from the front, and stick the dough edges together firmly at the overlap.,Stretch out Step 9 flatly by hand, and cut 5 notches with a bench scraper.,Roll up from the left, and firmly secure the ends of the dough together.,Coat the mold well with butter, place the dough from Step 11 with the seam facing the center into the mold, cover with plastic wrap, then with a wet cloth, and ferment again for 20~30 minutes.,When dough has fermented all the way to the top of the mold, bake for 14~18 minutes in an oven preheated to 180C.,Let cool, sprinkle powdered sugar sifted through a tea strainer, and it is done.